On lawn and garden tractors, there is often mounted a relatively large mower deck utilizing three or more spindles. In some instances it is desirable to discharge the grass back onto the ground. However, in other instances it is desirable to collect the grass clippings and to move them into a collector normally mounted on the rear of the tractor. When the latter is desired, the volume of grass being discharged by the mower is such that it requires that it be impelled by an auxiliary blower system in order to move it upwardly and rearwardly to the container. When the volume of grass is extremely large or when it is in extremely green condition, the blower must be of such size that it will require an auxiliary engine or motor to run the blower and to move the grass. Generally the module consisting of the blower and its auxiliary engine is mounted on one side of the tractor and at least part of the module will extend beyond the outboard side of the tractor wheels. In typical fashion the mower will move the grass to an intake side of the blower and the blower will then move the grass upwardly and rearwardly to the waiting container. Since most lawn and garden tractors are relatively small, the additional equipment of the module and the container serves as obstructions when they are not needed. It is therefore desirable to remove both when they are not needed. The auxiliary engine is generally heavy and requires a sizable frame structure for mounting it on the tractor. Also, since it projects outwardly of the tractor wheels and since smaller tractors generally have high maneuverability, the entire module can often be accidentally damaged through a quick turn or a fast reverse action by the tractor. Also in commercial mowing there may be several tractors used, only part of which requires the module. Consequently it may be desirable to move the module from tractor to tractor as the demand for the module is needed. Also, since the module is a relatively expensive item, it is desirable that a single module be utilized for several tractor and mower systems as it may be required. Thus, the owner of a series of tractors in commercial mowing may have only one module for use on several tractors.